1. Field of the Invention
The present invention relates to a culture apparatus.
2. Description of the Related Art
There is known a culture apparatus that cultures culture such as a cell, a microorganism and the like in a culture chamber. This type of culture apparatus includes a housing in which the culture chamber is formed, a door for sealing the culture chamber, and an ultraviolet lamp that generates an ultraviolet ray for disinfecting air in the culture chamber, and it is configured such that when detecting sealing of the culture chamber with the door, the ultraviolet lamp is on for a predetermined time period.
The ultraviolet lamp disinfects water for humidification in a humidification tray located on a bottom face of the culture chamber, for example, and as a means for detecting sealing of the culture chamber with the door, a micro switch or the like is used which is configured such that the switch is in an OFF state when the door is open, while the switch is in an ON state when the door is closed.
An operation of sealing the culture chamber with the door is performed after a user opens the door to take out culture from the culture chamber or after the user places the culture in the culture chamber, for example, and at each time the operation is performed, the ultraviolet lamp is on for a predetermined time period. As a result, the air, water for humidification and the like in the culture chamber are disinfected, which are contaminated by bacteria in the atmosphere since the culture chamber is opened.
Irradiation time of the ultraviolet ray from the ultraviolet lamp for disinfecting bacteria is experimentally obtained in advance, and the predetermined time period during which the ultraviolet lamp is on at each lighting is set on the basis of this experiment results, for example (See Japanese Patent Laid-Open Publication No. 2000-166536).
In the culture apparatus including the above-mentioned configuration, as the operation of opening/closing the door of the culture chamber is repeated, an irradiation output of the ultraviolet lamp is lowered due to the repetition of irradiation of the ultraviolet lamp. That is, since the irradiation output of the ultraviolet lamp is gradually lowered according to lighting time period (aging characteristics), a disinfection effect of the ultraviolet ray (that is, disinfection capability of the ultraviolet lamp) generated by the ultraviolet lamp per predetermined time period is also lowered according to the lighting time period of the ultraviolet lamp.
Thus, the more time the lamp is used, the more insufficient the disinfection in the culture chamber performed by the ultraviolet ray from the ultraviolet lamp becomes. That is, there is lowered the disinfection effect of the ultraviolet lamp accompanied by the culture chamber being sealed with the door. In this case, there is a risk that the bacteria remaining in the culture chamber without being disinfected might grow and contaminate the culture.